Conventional motor vehicles are provided with manually controlled tail and headlights, and automatic backup (white) lights and stop (red) lights which are activated whenever the foot brake is being applied. However, there are numerous occasions and conditions when the stop lights are not activated, particularly during the final stages of deceleration, as for example, during stationary or slowly moving traffic. Drivers of clutch-equipped transmissions sometimes declutch without braking with the result that the stop lights are not activated. Also on moderately steep hills, with automatic transmission vehicles, some drivers tend to "play" the accelerator or, if the vehicles have manual transmissions, to "slip" the clutch while depressing the accelerator to avoid rolling backwards. Other drivers utilize engine compression for braking or a shift downward, with either manual or automatic transmissions. Additionally, conventional leading vehicles lack means for automatically warning drivers-to-the-rear when it is traveling at slow speed and under conditions (egs.: dusk, inclement weather, poor visibility) where sudden stopping is a distinct possibility.
Proposals have been made heretofore to provide vehicles with warning expedients, but these are subject to numerous shortcomings and disadvantages sought to be obviated by this invention. In general, prior proposals involve moving components subject to malfunctioning, or necessitating substantial additions to or modification of portions of a conventional motor vehicle, or which are otherwise subject to undesirable limitations or shortcomings. For example, in U.S. Pats. Nos., Mitchell (2,486,864) proposes a slow travel blinker coriza (2,566,544) proposes a brake-operated slow signal indicator; Petrella et al (2,750,578), Dawg (2,957,161), Combs (3,109,158), and Carlson (4,320,384), each show a slow travel warning system under the control of a vehicle accelerator pedal. Warren et al (2,764,962) proposes a vacuum-operated slow travel indicator. Rapp (2,832,864) discloses a ball governor-operated warning system off of a spedometer cable, and Nordlund (2,974,304) proposes a complex pulse-echo sonic-sensitive warning system.